I liked the futuristic stuff better, but that's just my personal preference and definitely the minority from what I can tell.
I found this post on the overwatch subreddit regarded pre-ordering, the guy made some really good points that should be kept in mind for this too (and any pre-order)..
"What's the point of pre ordering now?"
The same as with every other pre-order: There is no point for you, the customer. It's great for the company though.
They get the money sooner. That helps with liquidity, especially because they have to pay for developers in advance of selling a single game.
They have much better numbers to show to their share-holders.
Since you have to make an extra effort to get a refund if you change your mind (for example because of bad reviews), you are more likely to ignore it, and they get to keep the money anyway.
If you wait too long with refunding, they get to keep the money anyway.
But most importantly:
You pay them money, no you are (both literally and metaphorically) invested into the game. You're more likely to hype it, to talk about it, and to be positive about it, because else you would have to face the reality that you wasted money, and most people would rather lie than admit a mistake. Basically you pay them to be their marketing fanboy zombie.
I was actually just thinking about it and i would prefer for it not to be ww1 and ww2 kind of stuff because lets be honest it's kind of boring having only a few guns, it was awesome playing them 10 years ago though.